Here's Why Packaged Guacamole Stays Green
With its vibrant colors and fresh ingredients, guacamole is at its most delicious and appealing when it is first served. But just like that leftover half of an avocado you stuck in the fridge, guacamole will turn brown over time if it isn't stored properly. And once guacamole has that brown tinge, it's a lot less tempting to dip into.
Fresh guacamole turns brown so quickly, it makes you wonder how the guacamole you find in stores is able to maintain that bright green avocado color from the time it's made to when it's packaged, transported, and finally sitting on the grocery shelves waiting to be purchased. The answer is in the way companies package their guacamole so it can withstand the process. And if you apply some of these food industry tricks in your own kitchen, you can make your homemade guacamole last a lot longer as well.
It isn't exposed to air
The biggest problem that manufacturers have to avoid is air. When avocados are exposed to air, they begin to oxidize. That's when and why they start to turn brown. But if you can eliminate any contact with air, guacamole — or even an avocado half — can be stored for longer without changing colors. That's largely why placing half an avocado face-down in water inside the fridge works, among other options (via Avocados From Mexico).
As for the pre-packaged guacamole, companies use one of three methods to keep it from turning brown, according to PowerFoodHealth. The first option to eliminate contact with oxygen is to place the guacamole in a container that can be vacuum sealed to remove all the air. Another method involves making sure the plastic is in contact with the dip itself so, again, no air is in the package. Finally, those containers that do have some space at the top have gone through a process that replaces the air that was in the container with nitrogen gas.
While that last one might be hard to duplicate at home, you can store your guacamole in a vacuum-sealed bag if you have the tools, or you can simply press plastic wrap down onto the guacamole before sealing it up in an airtight bag or container. Real Simple even suggests covering the guacamole with water and then pouring it off before eating it later.